Brush head for toothbrush

ABSTRACT

An elongated toothbrush head defining a longitudinal axis includes a first brush member having a first brush support surface and a second brush member which is a pivot arm mounted for pivotal movement on the first brush member. The pivot arm has a second brush support surface including a first portion and a second portion which are joined together and include free ends which are spaced apart. The first portion and the second portion of the second brush support surface are capable of pivoting relative to the first brush support surface about an axis which extends transversely to the longitudinal axis of the head and laterally across the pivot arm. One or more teeth cleaning elements project from the first portion and the second portion and are inclined at an angle to the second brush support surface.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/430,280 filed on May 9, 2006 now U.S. Pat. No. 7,448,107 which is acontinuation of U.S. patent application Ser. No. 10/697,206 filed onOct. 30, 2003 now abandoned which is a continuation of U.S. patentapplication Ser. No. 10/456,769 filed on Jun. 6, 2003 (U.S. Pat. No.6,760,946) which is a continuation of U.S. patent application Ser. No.09/425,423 filed on Oct. 22, 1999 (U.S. Pat. No. 6,574,820).

FIELD OF THE INVENTION

The invention relates generally to the field of oral care, and inparticular to toothbrushes. More specifically, the invention relates toa brush head for a toothbrush.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 5,577,285 (the '285 patent) discloses an electrictoothbrush with a rotary bristle supporting structure. In one embodimentof the invention shown in FIG. 6, the brush head is driven such that anouter ring of bristles 45 a and an inner ring of bristles 45 b are movedin an alternating rotary motion in opposite directions. While such anarrangement is beneficial for cleaning, for example, the bucal orlingual tooth surfaces, the lack of motion of any of the bristles in anup and down pattern results in a less than optimal cleaning of theinter-dental tooth surfaces.

FIG. 9 of the '285 patent discloses an additional embodiment of theinvention in which all of the bristles 45 are rotated about an axis 54while also being moved in an up and down motion parallel to this axis.This embodiment will provide enhanced cleaning of the inter-dental toothsurfaces. However, the fact that all of the bristles are moved up anddown limits the depth of penetration that the bristles can obtainbetween the teeth. This is because while some of the bristles are tryingto penetrate between the teeth, others are pressing against, forexample, the bucal tooth surface, thus limiting the motion of the brushhead towards the teeth.

SUMMARY OF THE INVENTION

The present invention is directed to overcoming one or more of theproblems set forth above. Briefly summarized, according to one aspect ofthe present invention, a head for an electric toothbrush, includes afirst bristle support which is rotatable about an axis and a pluralityof first bristles extending from the first bristle support. A secondbristle support includes a plurality of second bristles extending from asurface of the second bristle support at an acute angle to the surface.

These and other aspects, objects, features and advantages of the presentinvention will be more clearly understood and appreciated from a reviewof the following detailed description of the preferred embodiments andappended claims, and by reference to the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an electric toothbrush head attached to a brushhandle/drive;

FIG. 2 is an exploded side view of the toothbrush head;

FIG. 3A is a side view of the head with a central bristle in a retractedposition;

FIG. 3B is a side view of the head with a central bristle in an extendedposition;

FIG. 4 is a top plan view of a second embodiment of an electrictoothbrush head;

FIG. 5 is a sectional view of FIG. 4 taken along the lines 5-5;

FIG. 6 is a sectional view of FIG. 5 taken along the lines 6-6;

FIG. 7 is a sectional view of FIG. 5 taken along the lines 7-7;

FIG. 8 is a sectional view similar to FIG. 5 of a third embodiment ofthe invention;

FIG. 9 is a sectional view of FIG. 8 taken along the lines 9-9;

FIG. 10 is a sectional view of FIG. 8 taken along the lines 10-10;

FIG. 11 is a sectional view of FIG. 8 taken along the lines 11-11;

FIG. 12 is a sectional view of FIG. 8 taken along the lines 12-12;

FIG. 13 is a perspective view of a fourth embodiment of a toothbrushhead; and

FIG. 14 is a front view of the toothbrush head of FIG. 13.

DETAILED DESCRIPTION OF THE INVENTION

Beginning with FIG. 1, an electric toothbrush head 10 includes a neck 12which is connected to a bristle support 14. Bristles 16 on support 14are oscillated in a rotary movement through an arc of between about +−15to 90 degrees, more preferably +−20 to 50 degrees as in a conventionalelectric toothbrush.

FIG. 2 shows support 14 in an exploded side view. An interdental probe18 is secured to a slider core 20 in the center of bristles 16. Probe 18can be a single large bristle or a tuft of much smaller bristles.Alternatively, core 20 can be enlarged to accommodate a plurality ofprobes (not shown), one of which may be positioned in the center of thecore (as in FIG. 1), with the remainder of the probes being positionedon the core away from its center.

A pair of cam follower pins 22 are secured to opposite sides of thelower portion of core 20. Core 20 is positioned inside of a brush base24 such that pins 22 are forced to ride along respective cam tracks 26as well as respective vertical slider tracks 28 (one slider track ishidden behind the other). A retaining pin 30 rides in a track 32 toretain base 24 within a housing 34. A guide/rotation pin 36 passesthrough a hole in the bottom of housing 34 and is secured to base 24.

Operation of support 14 will be explained with reference to FIGS. 2, 3Aand 3B. Pin 36 is oscillated about its long axis by a drive mechanism(not shown) in neck 12. The drive mechanism can be of conventionaldesign. Oscillation of pin 36 causes brush base 24 and bristles 16 tooscillate in a rotary pattern. Pin 30 retains base 24 within housing 34.Oscillation of base 24 causes core 20 and probe 18 to oscillate with thebase because pins 22 ride in track 28 of the base. Pins 22 also ride inrespective tracks 26 in the housing, thus causing core 20 and probe 18to move up and down relative to bristles 16 during oscillation of brushbase 24. FIGS. 3A and 3B show that a preferred extension of probe 18from its lowest to highest position is about 5 mm.

In an alternative embodiment, all of bristles 16 are eliminated, leavingonly probe 18 for cleaning teeth. This embodiment would be usedprimarily for cleaning interdental spaces, not for cleaning the othersurfaces of teeth.

Turning to FIGS. 4-7, a second embodiment of the invention will bedescribed. A brushhead 40 can be attached to a handpiece (not shown) ofan electric toothbrush. A driveshaft (not shown) protrudes out of thehandpiece and can effect an oscillating rotation. Brushhead 40 includesa tube 42 in which a shaft 44 is located. The rear end of tube 42 fitsinto the housing (not shown) of the handpiece. Shaft 44 engages thedriveshaft of the handpiece. A pin 46 is press fitted into shaft 44. Pin46 can rotate at its free end in a bearing hole 48 in a front part 50 oftube 42. Axis 52 of pin 46 coincides with the axis of the driveshaft ofthe handpiece.

A pivot 54 can rotate in a bearing hole 56 situated in front part 50 oftube 42. Pivot 54 is retained in hole 56 by a ring 58. A first brushmember comprising a brush base 60 is press fitted onto pivot 54. Brushbase 60 has a first brush support surface 61 with holes 62 in whichtufts of bristles 64 are secured. A cross pin 66 is welded onto the freeend of pivot 54. Both ends of cross pin 66 retain brush base 60 on pivot54 by interaction with a shoulder 68 of the brush base. The central partof cross pin 66 is placed in a bearing hole 70 of a second brush membercomprising a pivot arm or rocker 72. Rocker 72 can swivel about crosspin 66 and has a second brush support surface 71 which contains holes 74in which tufts of bristles 76 are secured.

The pivot arm or rocker 72 comprises a first arm 73 and a second arm 75which define a first portion 77 and a second portion 79 of the secondbrush support surface 71. The first portion 77 and the second portion 79of the second brush support surface 71 are joined together and have freeends 81 and 83 which are spaced apart. The first portion 77 and thesecond portion 79 of the second brush support surface 71 are capable ofpivoting relative to the first brush support surface 61 of the brushbase 60 about an axis of cross pin 66 which extends transversely to alongitudinal axis of the head 40 and laterally across the pivot arm orrocker 72.

Shaft 44 includes a bearing hole 78 in which a drive rod 80 can move.The distance between axis 52 of pin 46 and an axis 82 of drive rod 80 isa radius r1. A stud 84 is welded onto the free end of drive rod 80. Thedistance between an axis 86 of pivot 54 and an axis 88 of stud 84 is aradius r2. Stud 84 can move in a bearing seat 90 in brush base 60. Atone end of stud 84 is carried a ball 92 which can move in a cylindricalslot 94 in rocker 72.

When shaft 44 is oscillated about axis 52 through an angle of +−alpha 1about pin 46, two different motions are induced. First, brush base 60and rocker 72 are oscillated in a rotating manner through an angle of+−beta 1 about pivot 54 in bearing hole 56. This oscillating rotationcauses bristles 64 to wipe plaque off teeth like a broom. Second, rocker72 is oscillated in a rotating manner through an angle of +−gamma 1about cross pin 66 in bearing hole 70. Oscillation of rocker 72 aboutpin 66 causes bristle tufts 76 to loosen plaque like a chisel. Twocycles of oscillation of rocker 72 about pin 66 occur for every onecycle of oscillation of base 60 and rocker 72 about pivot 54. Therelations between the oscillation angles alpha 1 to beta 1 and alpha 1to gamma 1 depend only on radii r1 and r2.

Referring to FIGS. 8-12, a third embodiment of the invention will bedescribed. The third embodiment modifies the relationship between theoscillation angles, primarily to increase the gamma angle of theoscillating rotation of rocker 72. The basic features of the thirdembodiment remain unchanged from the second embodiment. The maindifference is in the location of the drive rod.

In the mid-position of the oscillating rotation of a shaft 100, a driverod 102 is located at a distance e from a median plane 104 of abrushhead 106. A stud 108 is welded laterally on a free end of drive rod102 with a distance e between the center-lines. Stud 108 is movable in abearing seal 110 of a brush base 112. When a drive shaft 114 is in amid-oscillation position, stud 108 is in a median plane 116 of brushbase 112. Drive rod 102 can move in a bearing hole 118 in shaft 114.Bearing hole 118 is situated in the distance e from median plane 104 ofshaft 114 when the shaft is in its mid-oscillation position.

When shaft 114 is oscillated about median plane 104 through an angle of+−alpha 1, two different motions are induced. First, brush base 112 androcker 72 are oscillated in a rotating manner through an angle of +−beta2 which is smaller than +−beta 1 about axis 120. Second, rocker 72 isoscillated in a rotating manner through an angle of +−gamma 2 which isbigger than +−gamma 1 about cross pin 66. The relations between theoscillation angles alpha 1 to beta 2 and alpha 1 to gamma 2 depend onradii r1 and r2 as well as on the distance e.

In embodiments 2 and 3 of the invention, one component of the rockingmotion of rocker 72 causes bristles 76 to move up and down (i.e.substantially parallel to pivot 54) relative to bristles 64.

FIGS. 13 and 14 disclose a toothbrush head 130 which is similar infunction to the head of FIG. 4. The major difference is that tufts ofbristles 132 on a pivot bar 138 are tilted away from the perpendicular(to the top surface 140 of the pivot bar 138) at an angle 134 of betweenabout 1-20 degrees. Preferably the bristles 132 are tilted along thedirection of oscillation of bristles 136 on a brush base 142. Suchtilting of bristles 132 provides better interdental penetration duringthe respective upstrokes of pivot bar 138, particularly for the tuft(s)on bar 138 which are being moved by head 130 in the tilt direction. Itis preferable that tufts of bristles on both sides of bar 138 have thesame tilt angle and are tilted in the same direction (i.e. in the sameplane). Alternatively, tufts of bristles on opposite sides of the barcan be tilted in opposite directions. As shown in FIGS. 13 and 14, whenpivot bar 138 is oscillated relative to brush base 142, the top surface140 of pivot bar 138 and the top surface 144 of brush base 142 arecapable of lying in substantially a same plane (when pivot bar 138 isaligned with brush base 142) during the operation of the electrictoothbrush.

The brush support surface 140 of the pivot bar 138 includes a firstportion 141 and a second portion 143 which are joined together and havefree ends which are spaced apart. The first portion 141 and the secondportion 143 of the brush support surface 140 are capable of pivotingrelative to the brush support surface 144 of the brush base 142 about anaxis which extends transversely to a longitudinal axis of the head 130and laterally across the pivot bar 138.

The invention has been described with reference to several embodimentsincluding a preferred embodiment. However, it will be appreciated thatvariations and modifications can be effected by a person of ordinaryskill in the art without departing from the scope of the invention.

1. An elongated toothbrush head defining a longitudinal axis, saidtoothbrush head comprising: a first brush member having a first brushsupport surface; a second brush member comprising a pivot arm mountedfor pivotal movement on the first brush member, the pivot arm having asecond brush support surface including a first portion and a secondportion, the first portion and the second portion of the second brushsupport surface being joined together and having free ends which arespaced apart; the first portion and the second portion of the secondbrush support surface being capable of pivoting relative to the firstbrush support surface about an axis which extends transversely to thelongitudinal axis of the head and laterally across the pivot arm; andone or more teeth cleaning elements projecting from the first portionand the second portion and inclined at an angle to the second brushsupport surface.
 2. The toothbrush head of claim 1, wherein: the firstportion and second portion of the second brush support surface arespaced apart longitudinally.
 3. The toothbrush head of claim 1, wherein:the teeth cleaning elements on the first portion and the second portionare inclined at an acute angle to the second support surface.
 4. Thetoothbrush head of claim 3, wherein: the first brush support surface hasone or more teeth cleaning elements mounted substantially perpendicularto the first brush support surface.
 5. The toothbrush head of claim 3,wherein: the teeth cleaning elements on the first portion and the secondportion are inclined in the same direction.
 6. The toothbrush head ofclaim 3, wherein: the teeth cleaning elements on the first portion andthe second portion are inclined in opposite directions.
 7. Thetoothbrush head of claim 3, wherein: the teeth cleaning elementscomprise at least one tuft of bristles adjacent to the free end of thefirst portion and at least one tuft of bristles adjacent to the free endof the second portion which are inclined in the same direction.
 8. Thetoothbrush head of claim 3, wherein: the teeth cleaning elementscomprise at least one tuft of bristles adjacent to the free end of thefirst portion and at least one tuft of bristles adjacent to the free endof the second portion which are inclined in opposite directions.
 9. Thetoothbrush head of claim 3, wherein: the teeth cleaning elements on thefirst brush support surface comprise a plurality of bristle tufts whichare substantially perpendicular to the first brush support surface. 10.The toothbrush head of claim 3, wherein: the teeth cleaning elements onthe first portion and the second portion are inclined away from a lineperpendicular to the second brush support surface at an angle of about 1to 20 degrees.